This invention relates to an electro-optic device used for various display devices which display an image having a monochrome and/or colored tone partially light and shade or to an electro-optic device useful for optical valves, shades or screens.
Various electro-optical devices which present or show a peculiar electro-optical phenomenon in a relatively low electric field are well known in the art. Such electro-optical devices can be divided into two groups; one group including so-called crystalline liquids, that is, some of the organic substances presenting mesophase indicating that they are states of matter intermediate between the liquid and crystalline states or mixtures of these organic substances and the other group including so-called colloidal liquids which are obtained by dispersing a non-organic crystal such as tungsten oxide and vanadium oxide or an anisotropic crystal such as herapathite in a solvent, a typical one of which is the colloidal liquid on the market named VARAD (made by MARKS POLARIZED CO.)
When an electric field is applied to such an electro-optical matter, for instance a crystalline liquid; in one case, it changed its state, that is, it changes from a state of presenting an optical isotropy to a state of presenting an optical anisotropy, and in another case, it changes from the state of presenting an optical isotropy to a state of a molecular turbulent flow thereby to uniformly scatter incident light. In addition, a certain type of crystalline liquid matter selectively reflects only the light of a particular wave length upon application of an electric field thereto.
Such peculiar optical properties of crystalline liquid matter are utilized in a conventional crystalline liquid display device known in the art. Such a conventional crystalline liquid display device is provided with a plurality of electrodes for optical image-creating, confronted each other, on both side of a crystalline liquid film wherein electric field has been properly selectively applied to these electrodes, thus selectively displaying a part of or the whole of the image, but it has never been tried to present a light and shade portion in the image or to display a plurality of colored images. Accordingly, what is displayed by the conventional crystalline liquid display device is limited to characters or simple figures.
The present invention is to solve such difficulties accompanying the conventional crystalline liquid display device. In this invention, its electrode is divided into a plurality of parts, external input voltages necessary for the occurrence of an electro-optical phenomenon in these parts thus divided being made different from one another thereby to display an image having various brightnesses and/or color tones different from one another in the parts.